1. Field of the Invention
The invention relates generally to devices for dispensing fluids, and more particularly, to an improved device for dispensing beverages.
2. Description of Related Art
Dispensing devices, particularly dispensing valves for controlling the flow of a fluid from a container, are well known in the art. An example of such a device is a valve for dispensing frozen or liquid, gas saturated or unsaturated beverages. Frozen carbonated beverage machines are known in the art and have been used for years. These devices produce a frozen carbonated beverage by freezing a mixture of ingredients including syrup, water and carbon dioxide in a mixing chamber. The mixture freezes on the inner surface of the mixing chamber that is surrounded by a helical coil through which a refrigerant passes. A rotating shaft disposed inside the chamber has a plurality of outwardly projecting blades that scrape the mixture off the inside wall of the mixing chamber. Once the carbonated beverage is in the desired frozen state, the product is dispensed from the chamber through a dispensing valve.
During the process of dispensing beverages through dispensing valves, a pressure reduction occurs. If the beverage contains dissolved gases at or near the saturation levels, when the pressure is reduced through a valve, a release of a portion of the dissolved gases will occur.
Known dispensing valves for dispensing gas saturated frozen and liquid beverages are typically designed to retain the highest possible level of dissolved gases. When the associated pressure reduction occurs, some of the energy from the reduction in pressure is converted to turbulent flow. This effect causes the release of some of the dissolved gases in the beverage. The design of the dispensing valve can cause more or less turbulence, thus releasing more or less of the dissolved gas.
Similar effects are observed when a bottled beverage is opened without first shaking the bottle, versus opening the bottle after shaking it. If the bottle is not shaken, a much smaller amount of dissolved gases will be released than if the bottle is first shaken. The turbulent shaking causes instability of the dissolved gases, which are released upon opening. In most cases, the beverage is also chilled to increase the solubility of the gases in the beverage.
As in the case of sealed bottles, a flowing dispensed beverage is cooled prior to dispensing and the beverage at the higher pressure is maintained at or near saturation. The desired effect in most cases is to serve a beverage at the lower atmospheric pressure, which retains gas content at or near saturation.
Foaming is also a problem that occurs when a gas saturated beverage is dispensed from a higher pressure to a lower pressure. Minimizing turbulence in flow or dispensing will reduce the effect of foaming. This problem is exhibited when beer is dispensed. Excess foaming will occur if the pressure reduction is too great or excess turbulence occurs during the dispense cycle. Diet beverages foam excessively if the pressure reduction is too great. While these two beverages are more sensitive to foaming due to their composition, all gas saturated beverages have this problem to a lesser degree.
Turbulence can occur in the supply line feeding the beverage dispensing valve. Lines that are sized too small or have fittings creating excessive pressure drop can create "turbulent flow" and produce an unstable beverage prior to dispensing from a valve. This is similar to shaking a bottle of beverage prior to opening. The obvious solution to the line turbulence is to size lines as short as possible and as large in diameter as possible and with few fittings. This will reduce turbulent line pressure drop that creates an unstable beverage.
Release of dissolved gases when dispensing a gas saturated frozen beverage can create additional problems. When the frozen beverage is dispensed, foaming occurs which creates a drink that has a volume greater than the volume of dispensed liquid. This desirable effect is called "overrun." However, if the resulting frozen beverage with overrun has been dispensed in a turbulent manner, the drink will dispense into a cup that will appear full. The frozen beverage will then release the unstable gas, causing the volume in the cup to become much smaller (collapse) and denser (less overrun). This is a very undesirable trait.
Thus, a need exists for a dispensing device that addresses the shortcomings of the prior art.